Automatic stoking device



June 21, 1932. F, w, CD02 1,863,677

AUTOMATIC STOKING DEVICE Filed Nov. 12. 1928 3 sheets-sheet 1 Jp/ A j? Gand/ June 21, 1932. F. W, VODOZ 'I 1,863,677

` AUTOMATIC STOKING DEVICE Filed Nov. 12. 1928 sheets-sheet 2 AUTOMATIC STOKING DEVICE Filed Nov. 12. 1928 .s sheets-sheet 's I 25 z J0 5M a 4 I ./7/wl0f f 1,74 Crick w. ogg

Patented June 21, 1932 FREDERICK W. VODOZ, F WILMETTE, ILLINOIS AUTOMATIC STOKING DEVICE Application mea imvemberv 1a, 192s. serial No. 318,682.'

This invention relates to-improvements in automatic stoking devices for furnaces and has for its principalobj ect to provide an im'- proved form of Stoker and automatic con- 5 trolling means therefor, responsive to varia-.

tions in volume of fuel in the fire box.

Means have heretofore' been proposed for automatic feeding devices of the volume responsive type` above described, said means consisting of a system of levers having engagement with the 'upper surface of the fuel bed, but such proposals have-been limited, so far as I am aware, to an under fed vtype of Stoker.

In carrying out my invention I provide an improved form of controlling means including a fire contact member which is automatically raised or lifted from the fuel during the feeding operation and the coal is fed by 30 gravity on the top of the fire of the fuel bed whereby the stoking apparatus is adapted to handle a wider variety of kinds of coal than is possible with under feed stokers which are capable of handling certain -restrict-ed classes of coal. Means are also provided'for permitting the lire contact member to drop by gravity upon the top o f the fuel bed so as to break down any crust which may be formed by arching of the coal.

As a further feature of my invention, I

provide an improved form of apparatus including water cooling means for the portion of the fire contact member, which cooling means may also be used in connection with an auxiliary hot water supply system. I also provide shaking means automatically operated simultaneously with the fuel feeding means so as to shake down the ash and assure a substantially continuous automatic operation of the fuel replenishing apparatus. 'In the preferred form shown, my fuel 'charging and shakingapparatus is constructed asa unitary attachment capable of being applied to a furnace of standard construction by merely hinging the same in place of the ordinary fuel charging door thereof.

The invention may best be understood by.

reference to the accompanying drawings, in which Figure 1 is a view in part elevation of a furnace of the ordinary household type to o which my invention has been applied, with parts broken away to show certain details of the operating mechanism.

.Figure 2 is an enlarged horizontal section 55 taken generally on line 2-2 of Figure l, but with certain parts omitted and other parts broken away.

F'gure 3 is a section taken on line 3 3 of Figure 2.

Figure 4 is a vfront View of the apparatus shown in Figure 1.

Figure 5 is a detail section taken on line 5 5 of Figure 2. l i

Figure 6 is a diagrammatic view of the de- 65 vice showing the control means in position to automatically start the fuel feeding operation.

Figure 7 is similar to Figure 6, but shortly after the fuel feeding means has been put into operation and the volume control contact arm has been raised out of the way to permit fuel to be fed to the-top of the fire.

'Figure 8 is a diagrammatic View somewhat similar to Figure 4, but showing the parts 75.

in position for shaking down the fire.

' Figure 9 is a wiring diagram of the electrical control means for the feeding and shaking motor, and

Figure 10 is a diagrammatic' view showing 80 one form in which the water cooling system may be arranged to provide an auxiliary supplg` of hot water. i v

igure 11 is a diagrammatic view of a thermal time switch forming part of the electric control system.

Referring now to details of thedevice illustrated in the drawings and embodying one form in which my invention may be utilized,

10 indicates a hot-air furnace of the ordinary 90 i household type including a fire box 11, grate 12 and ash p1tl3 having an inlet draft opening 14, all of the usual construction.

In the form shown the grate 12 is of the' mushroom type supported at the center portion on an upright finger 12a carried. on a cross support 12b, in the usual manner. It will be understood that this specific type of furnace is utilizedamerely as a means of illustration of my invention, and that my im- 10 brackets 18, 18. Sai

gi-oved means can, with slight modification, applied to a wide variety of coal, coke, etc., burning furnaces adapted not onl for heating houses but in steam generating plants, and the like.

In the form shown, my improved stoking device is constructed as an attachment to be applied as a unit to the fuel supply opening 15 at the front of the furnace, a portion of said apparatus extending through said opening and suitably supported, as for instance by hinges 16, 16 on hinged in 17 in supporting hinged pin and brackets, in the form shown, comprise the hinged pin and ysupporting bracket for the regular iire door which lmy apparatus replaces.

The main portion of the apparatus comprises a coal hopper 20 supported on a conveyor casing 21 to which the hinged supports 16, 16 are connected. The casing 21 closes the fire door opening 15 and is provided with a chute or extensionV 22 projecting into the furnace through said opening, as shown in Figures 1, 2 and 3. Said chute extendsbeyond the side wall of the lire box 11 and has a floating fuel contact member 23 mounted on its inner end. In the form shown, said fuel contact member comprises a hollow elongated casting 24 connected at opposite ends through a pair of pipes 25, 25, to fittings 26, 26 pivoted by water-tight joints on opposite sides of the chute 22, as shown in Figures 1, 2 and 3.

The floor of the chute 22 is formed of a side walls 29, 29. The two inclined upper walls 30 and 31 meet at a transverse ridge 32, as best shown in Figure 3, substantially in line with the side walls of the tire box 11. A central wall 29a divides the compartment 27 into two parts, as shown.

The compartment 27 just described is adapted to form part of the water cooling system. Water is supplied to one side of the compartment by inlet pipe 34 from thence it communicates with the interior of the hollow :fuel contact member 24 through pipes 25 and pivotal fittings 26,'and thence to the other side of the compartment and the outlet pipe 35 which may, if desired, be connected with a supply tank 36, as shown in Figure 10, to supply an auxiliary of hot water for household use.

In the form shown, a fuel gate 38 is arranged over the transverse ridge 32 in the chute and is pivoted at its upper end on pins 39, 39 carried by side Walls 37, 37 of said chute. The arrangement is such that the gate 38 is free to swing -inwardly toward the fire when coal is fed upwardly along the bottom wall 30 of the fuel passage, as will hereinafter more f ully ap ar. A

The means or feeding the, fuel to the hopsecured to the outer end ofthe conveyor casing 21. A conveyor screw thread 48a is mounted on the inner end of the shaft 47 within the casing 21, said screw thread being arranged when rotated to discharge coal deposited within said casing by gravity'from the hopper 20 into the fuel chute 22.

A cam member 50 is iixed on the outer end of the shaft 47, said cam member being arranged to cooperate with a bell crank lever 51 mounted on stud 52 which herein is an extension of screw shaft 41 at one side of the support 47a. In the form shown said bell crank lever includes an arm 51a of L-shape bent into engaging position with the cam 50 as clearly shown in Figure 2. The other arm 516 of said bell crank lever extends in a generally downward direction and has a rod 53 connected thereto extending through the side of the furnace into engagement with a lever 54 connected to one of the,pivotal fittings 26 of the contact member 23.

. The electric control means for the feeding motor 40 comprises a spring contact member 55 carried on a fixed support 56 and having its `outer end adapted to engage a segment 57 carried on the bell crank lever 51. The

segment 57 is provided w1th a dead spot 58 1.

com rising a suitably insulated section. The dead) spot 58 when in position to be engaged by the spring contact 55 serves to break the operating circuit for the driving motor 40, as shownin Fig. 9. i

The circuit connections are indicated in the latter figure and include a source of cur' rent supply, such as a receptacle 60 having one power line 61 leading through a thermal switch 66` to the segment 57 and another line 62 leading from the spring contact 55 through motor windings 63, armature 64 and main current line 65 to the plug 60. The thermal switch 66 is shown in detail in Fig. 11, and comprises a heating coil 67 in series with the main conductor 61 and surroundi g a mer cury tube 67a. Electrodes 68 and 9 are disposed in the upper and lower endswof said tube, the upper electrode 68 being normally spaced above the level of mercury., but when said mercury is heated after a predetermined flow of current has passed through theheating coil 67, a short circuit connection is established through electrodes 68 and 69, conductor 69aso as to blow out fuse 6921 in series with conductor 65.

With this thermal switch properly adjusted, the charging mechanism is onl;7 permitted to operate continuously for a limited peg-iod, so as to eliminate the danger of over- I segment 57 on charging the lire in case the control member 23 fails to work properly.

The automatic shaking mechanism for the grate includes a rod eccentrically connected on pin 71\carried by the cam member 50 and extending to an upright lever 72 pivoted on pin 73 carried on fixed support 74 adjacent the base of the furnace and connected to the shaking rod 75 through link 76. Flexible safety means are preferably provided in the shaking connections described,

in the form shown said means including two springs 78 and 79 carried on rod 8() extending inwardly from the upright lever 72 parallel with connecting rod 70. Said rod 80 passes through a .projection 81 on the link 7 0 and engages between adjacent ends of springs 78 and 79 so that endwise movement of the link 70 is transmitted to the lever 72 through the springs 78 and 79.v Relative movement of the links 7() and 72 is also afforded by means of the pin 83 on lever 72 moving in slot 84 in-'said link. l

As will be seen from comparison of Figures 4 and 8, the horizontal oscillatory movement of link 7 6 servesto rock the grate 12 on its central supporting-finger 12a, and thus shakes down the fire in the usual manner.`

With the parts arranged as above described, the operation of the feeding and shaking mechanism will now be understood. With a normal and sufficient supply of fuel on the grate, as shown in Figure 1, the control member 23 will rest upon the upper surface of said fuel and through its connection with bell crank lever 51 the electrical contact 55 will engage with the dead spot 58 on segment 57 and the feeding and shaking motor 40 will therefore be inoperative so long as the floating contact member 23 is supported in the position shown in Figure 1.

After the fuel is consumed a predeterlnined amount so as to lessen its volume, the weight of the floating member 23 isV sufficient to drop by gravity with the upper surface of the fire until the point is reached as shown in Figure 6, when the spring contact 55 passes from the dead oint 58 to a live point of the bell crank lever 51. This establishes a circuit through the motor 40 so as to start the same and cause the cam member 50 to be rotated in a counter-clockwise direction, as seen in Figures 4 and 8. The motor is constructed to operate with suliicient momentum to carry the dead point 58 on bell crank lever 51 over the contact spring 55 and continue the operation of the motor on the live portion of segment 57 on the opposite side of said dead spot, as shown in Figure 7. At the same time the lever arm 51a of bell crank lever 51 engages with cam surface 50a of cam member 50 so as to raise the lever arm 51a and through the associated lever arm 51o of said bell crank and rod 53 act to positively raise the floating ,contact member 23 upwardly into the position shown in Figure 7. This raised position of the contact member 23 is maintained as long as the arm 51a is in engagement with the outer periphery 501) of the cam member 50, as shown in Figure 8 or somewhat more than a half revolution of said cam member. l/Vhile said cam member is rotating with shaft 47, said shaft is 'also operating the conveyor 48 to positively feed coal from the conveyor casing 21 into the feeding chute 22. As the coal is' fed into said chute, it passes upwardly along the inclined bottom wall 30 and is forced over the ridge 32 and through the swinging gate 38 so that a portion of it falls downwardly along the inclined wall 31 and onto the top of the fire.

The feeding and shaking movements are thus continued until the point 50c on said cam member passes beneath the arm 50a and permits said arm to drop into a recessed surface 50d of said cam member. This recess affords anabrupt drop so as to permit the floating weight 23 to drop heavily upon the upper surface of the fire, said floating member being preferably of substantial mass so that the dropping thereof will tend not only to afford a substantial contact with the upper surface of the newly supplied fuel, but also in cases where the fuel has a tendency to arch over the grate, the dropping of the member 23 is sufficient to break down any crust formed by su'ch arching. Itis manifest furtherthat the weight of the member23, may

in many instances, be suiicient to depress the upper surface of the fire before a substantial crust can be formed thereover,`

In the event that a sulicient amount of c oal has been fed to the fire, however, the floating member 23 will engage the top of the newly replenished fuel and lever arm 51a may not reach the bottom of depression 50d, but the segment 57 will be returned to a position in which the contact spring 55 again registers with the dead spot 58 thereby discontinuing further feeding and shaking operation.

In the event, however, that sufficient coal has-not been fed to the fire during one revoluytion of the cam member 50, the floating concycle of feeding and shaking movements through another complete revolution of the cam member 50 as that which has just been described. It will thus be clear that the vfeeding' and shaking movements will continue until such time as the fuel has been replenished to a point where the contactx member423 is -sustained at a predetermined level of the fuel at which level the spring 5 adapted to deposit fuel upon the top of the fuel bed in sald fire box, control means for said feeding means including a floating member adapted to contact with the top of said bed `of fire and responsive to variations in height thereof, and means for moving said floating member out of contacting position with the fire during operation ofl said feeding means.

2. In a furnace, a fire box, feeding means adapted to deposit fuel upon the top of the fuel bed in sa1d fire box, control means for said feeding means including a floating member adapted to contact with the top of said bed of fire and res onsive to variations in height thereof, an means connected with said control means for automatically moving said floating member out of contacting position with the `fire during operation of said feeding means.

3. In a furnace, a fire box, feeding means adapted to de osit a predetermined char e of fuel upon t e top of the fuel bed in said fire box, control means for said Vfeeding means including a floating member adapted to contact with the top of said bed of fire and responsive to variations in height thereof, and

means for moving said floating member out of contacting positionwith the fire during operation of said feeding means, and p ermitting said floating member to resume its contacting position upon completion of a single charge of fuel by said feeding means.

,4. In a furnace, a f ire box, feeding means adapted to deposit fuel upon the top of the fuel bed in said fire box, control means' for said feeding means including a floating member adapted to contact with the top of said bed of fire and responsive to variations in height thereof, and liquid cooling means for said floating member.

5. In a furnace, a fire box, feeding means adapted to deposit fuel up'on the top of the fuel bed in sa'idfire box, control means for said feeding means including a floating member adapted to contact with the top of said bed'of fire and responsive to variations in height thereof, and means for bodily raising said floating member and permitting it to fall by gravity upon the top of said fuel bed to break down accumulations of fuel formed during combustion thereof.

6. In a furnace, a fire box, feeding means adapted to deposit fuel upon the top of the fuel bed in said fire box including an electric motor, control means for said motor including a floating member adapted to contact with the top of said fuel bed, means operated by said motor for raising said floating member during operation of said feedmg means motor, and control means for said motor including a floating member adapted to contact with the top, of the fire bed in said fire box,

and electrical circuit connections for said motor controlled by said floating member.

8. In a furnace, av fire box, feeding means adapted to deposit fuel upon the top of the fuel bed in said fire box including an electric motor, control means for-said motor including a floating member adapted to contact Withthe-topof said fuel bed and responsive to variations in height thereof, electric circuit connections controlled by said floating member forstarting said motor, and meansoperated by said motor for raising said floating member during operation of said feeding means, and permitting said floating member to resume its height-responsive lcontrolling position relative to the fuel bed after a predetermined amount of fuel has been added to the fire box. p

9. In a furnace, a fire box, feeding means for injecting'fuel into said fire box, a motor for said feeding means, control means for said motor including a floating member ar' ranged to contact with the top of the fuel bed in said fire box, and responsive to variations in height thereoffmeans for moving said floating member out of contacting posi.- tion with the fuel bed during the operation of said feeding means, includinga cam driven by said motor.

10. In a furnace, a fire box, feeding means for injecting fuel into said fire box,l a mot-or for said feeding means, control means for said motor including a floatmg member ar- FREDERICK W. VODOZ. 12a 

